I use a geo: URI link, (combined with the arguments that Google Maps likes for after it's pulled up).
<a href="geo:37.44462,-122.16326?q=37.44462,-122.16326(CommerceNet)">CommerceNet</a>
Support isn't always there yet, but I think it's the closest to a standard that doesn't tie you to one specific app. Works on most mobiles, but didn't work on any desktop last I checked.
For a full solution, I actually combined that with both hCard and Schema.org data to produce a block:
<section itemscope itemtype="http://schema.org/GovernmentOrganization"
class="vcard">
<header>
<h3 id="contactState"
itemprop="name"
class="org fn"
style="margin-bottom:0;">SD State Capitol</h3>
</header>
<a href="geo:44.367064,-100.34588?q=44.367064,-100.34588(State+Capitol)"
itemprop="address"
itemscope itemtype="http://schema.org/PostalAddress"
class="adr"
style="font-size:medium !important;color:black !important;">
<div itemprop="streetAddress"
class="street-address">
500 East Capitol Avenue
</div>
<div>
<span itemprop="addressLocality"
class="locality">Pierre</span>,
<span itemprop="addressRegion"
class="region">SD</span>
<span itemprop="postalCode"
class="postal-code">57501</span>
</div>
</a>
</section>